GMO foods are safe to eat, but they pose challenges in the environment.

Many aspects of modern technology make people a bit uneasy, but genetically modified foods may be in a class by themselves. Labs all around the world make genetic modifications of organisms—bacteria, plants, and animals—365 days a year. And some of the results of that work have been ingested by humans for years, often in the form of life-saving drugs. But genetically modified crops remain controversial around the globe, and while they're commonly used in the US, they have almost no presence in the European market.

The worries about GMO foods largely focus on their safety, but much of the debate ignores the extensive studies that have been done to understand both the potential risks and what we've learned about them. In response to this perceived gap in understanding, a group of Italian scientists have now performed a comprehensive review of the scientific literature on GMO crops (we were made aware of the review by Real Clear Science). The results suggest that GMO crops are safe for us, but there are some remaining concerns about their environmental impact that need to be nailed down. In the meantime, the authors suggest that GMOs represent a serious challenge for science communication with the public.

To get a grip on current research, the authors searched databases for any papers on the topic that were published between 2002 and October of 2012; they came up with 1,783 of them. But not all of these spoke directly to safety. The authors note that many of the articles published on GMO crops were commentaries, and the ones that directly addressed safety concerns tended to end up in low-profile publications. Confusing matters further, there were several areas of largely unrelated research that all speak to the safety of these crops.

What you ingest

There's one obvious concern when it comes to GMO crops: we eat them. Are we ingesting anything unusual? To understand that, you have to know how transgenic plants work. They start with a piece of DNA, one that carries a gene of interest—say, one that encodes a protein that provides the plant disease or pest resistance. That DNA is packaged with additional sequences that make sure the gene can be made by plant cells, along with a gene for drug resistance that lets you track whether the DNA is present in cells. The whole package is then inserted into one of the plant's chromosomes.

Once in a plant cell, the gene gets transcribed into RNA. In some cases, that's the end of it; the RNA is active in some way that's useful (for example, it might target a virus for destruction). But in many cases, that RNA is converted into protein, such as the Bt protein that is toxic to insect pests. In a few rare cases, that protein may catalyze the production of a specific chemical. One example of the latter is golden rice, which has been engineered to carry the genes needed to produce vitamin A.

So DNA, RNA, proteins, and chemicals. That's a lot to worry about, right?

Well, maybe not. Everyone's meals normally contain some DNA, but the average person only ingests between 0.1 and 1 gram of it every day. Most of that is the DNA that all plants and animals naturally contain; estimates are that the engineered DNA accounts for less than 0.00006 percent of the total. Cooking destroys most of it, and the majority of the rest is degraded in the harsh digestive environment.

There's a small chance that some of it will survive long enough to be taken up by gut bacteria, but this is a very uncommon event (otherwise your average E. coli would have a genome swimming with corn and cow DNA). The one potential risk there is that the bacteria will pick up the drug resistance gene that's part of the initial package inserted into the plant, but that poses little risk since biologists use resistance genes that are already widespread in bacterial populations, meaning the drugs aren't used much clinically.

Similar things apply to the RNA and proteins, in that most are fully digested long before they reach the bloodstream. (In fact, the review notes that this is precisely why we have to rely on injections to get protein- and RNA-based therapies into people.) There's been a single report that plant RNA may appear in the bloodstream of mice, but the results haven't been replicated since.

Another risk is that the proteins made by the GMO plant (or some digested fragment of it) will cause an allergic reaction. For that reason, the protein sequences are tested against a large database of common allergens. The proteins are also assessed for toxicity in animals and for their ability to survive a digestive environment. As far as any chemical end products are concerned, they're generally being used precisely because the chemical in question will have a beneficial effect on humans. Because all these risks from DNA, proteins, and chemicals are identical to those posed by unmodified plants, the European Commission has concluded that "the use of biotechnology and of GE plants per se does not imply higher risks than classical breeding methods or production technologies."

The only residual uncertainty is whether the mere presence of the RNA and proteins made by the transgenic DNA alters the plants in a systematic way. In a general sense, they don't; transgenic plants pass what's called a "substantial equivalence" test, which means they are indistinguishable from the crop that they were derived from in terms of nutrients and other key components.

However, if you do a detailed analysis of every protein and chemical produced by the plants (a proteomics and metabolomics study), you can see differences between the transgenics and other crops. But similar things happen if you raise identical crops in slightly different environments, so it's not clear if this is a real result or an experimental glitch—and, if it's the former, whether that tells us anything significant. The review's authors argue that this is an area that deserves further study.

GMOs and the environment

Although it's almost impossible for the genes to spread to humans, that doesn't mean they can't spread. Crops are grown in uncontrolled environments, where they come in contact with other species, some of which can be close relatives. For most species, this DNA doesn't provide any advantages that can't be provided by the DNA that's already present in the environment. Bacteria and insects won't benefit from picking up genes for herbicide resistance or insect-killing proteins. The drug resistance could benefit the bacteria, except the genes in use are already widespread in soil communities. And at least so far, field studies haven't found any evidence of transgenes ending up in soil bacteria.

The same cannot be said for plants, or at least those plants that are closely related to crops. There have been reports of a strain of canola that contains multiple herbicide resistance genes, which presumably came about through the hybridizing of two or more GM strains. Obviously, the transgene would provide a survival advantage for any plant that was growing near agricultural areas. The same would be true for the spread of genes that encode proteins that are toxic to insects, except the latter would provide a survival advantage just about anywhere.

These genes could also cause problems for agriculture itself. Currently, resistance to insecticidal proteins like Bt is limited in part by careful crop management. If wild plants pick up the same gene, it could hasten the evolution of resistant insects regardless of how the crops are managed. Although there are some ideas about how to limit the spread, there are problems with all of them: "none of them can be considered completely effective for transgene containment and complete segregation of GE [genetically engineered] crops is not possible."

Communication breakdown

The conclusion of the review is that from the perspective of human consumption, all evidence indicates that GMO foods are safe; the primary risks are to agriculture itself, primarily from the unintended spread of some of the transgenes to wild populations.

But that's hardly the impression you'd get from the public debate. GM foods are often portrayed as untested or their safety a complete unknown. Rare, unreproducible results are often trumpeted as the final word. These are features that are shared with a number of other areas where there's been a failure of science communication, and the authors argue that scientists themselves share the blame here: "the frequent non-scientific disputes in the media that are not balanced by an effective communication from the scientific and academic world, greatly contribute to enhance the concerns on GE crops."

But the review points out that effective communication is hard because the scientific community is never 100 percent unified. The authors note that there is "animated debate regarding the suitability of the experimental designs, the choice of the statistical methods, or the public accessibility of data," and that's all a healthy sign that science is following its normal course here, even as its conclusions firm up. Unfortunately, this healthy debate has "frequently been distorted by the media and often used politically and inappropriately in anti-GE crops campaigns."

All of which makes getting the big picture—GM foods appear safe to eat—a difficult message to elevate above the noise.

335 Reader Comments

Improving the nutrients of an indigenous plant to provide something that's missing, like golden rice, is a great thing, and I fully support it.

Hardly a great thing, it's called diversity. We would be growing a single crop with all nutrients in it with that reasoning. And the African kids who become blind because of the missing vitamin A are seriously suffering from malnutrition, they are not just missing vitamin A. Give them a superconcentrate broth to cook their white rice, or give them the means to grow vegetables and pulse, but that Golden Rice is just plain wrong, although it's more politically and ethically than medically.

Besides, anyone who buys that a corporation like Monsato is interested in making sure People around the World receive nutrient rich food, is not seeing the reality. I would believe it if the food was given away for free. It never is. Even US Aid is paid for by taxpayer funds.

Corporations cannot control food revenue without controlling food production. A corporation cannot control a plant that is made for free by Nature. Solution: control the seed production and ensure farmers have to buy from you every season.

I'm just convinced that there's bound to be a lot of cheating and bribery going on behind the scenes when companies want to get their product out into the market. Hence my unwillingness to blindly trust all the papers and reports.

So tell me, what do you eat?Whether it is companies, or farmers, or shippers, or grocery stores, there are a large number of people making (or at least attempting to make) money from selling food. Unless you grow all of your own food, from seeds and animals that you have heavily tested yourself, you are blindly trusting someone.Why do you think that a farmer growing organisms modified by random mutations followed by selection for some traits is more trustworthy than a farmer growing organisms with an intentionally inserted specific mutation?

This so much this. The food supply chain is huge. Its hard to give an easy answer on how large it is as it spills over into dozens of different industry segments. But to compare everyone's favorite Boogeyman Monsanto to others in the food supply.Walmart takes 3 weeks in just food sales to hit the yearly revenue of MonsantoMcDonaldsCokePepsiCumminsCaterpillarKrogerSafewayWalgreenCVS CaremarkPublixSupervaluWhole FoodsMondelez KraftGeneral MillsKelloggLand O LakesConAgra Dead FoodsHeinz ADMTysonSmithfieldLeucadiaYumStarbucksDarden is not too far behindIt will be close for just the agr products for Union Pacific over Monsantos total revenues.SyscoCHSCostcoDowDupontYour food goes though a lot of hands. Despite all of the hands it goes though with as many meals eaten every day its amazing how safe our food supply really is.

Our food does not affect most of us in a negative for a few reasons:1. Food our bodies are used to digesting2. Packaging3. Labeling4. Handling5. Farming techniques6. Food temperature

As I have said before, why move to GMO if our food supply ain't broken?

Our food does not affect most of us in a negative for a few reasons:1. Food our bodies are used to digesting2. Packaging3. Labeling4. Handling5. Farming techniques6. Food temperature

As I have said before, why move to GMO if our food supply ain't broken?

1- huh? Outside of ethnic enclaves food is radically different then what we are used to eating in the United States 30 years ago and for those with European decent some of the food that is on market has never been consumed by your ancestors, the same goes for those of African, Asian and Native decent.

Pomegranate for example if you are of African, Native or Northern European decent there is an awesome chance that you are the first person in you lineage to eat one and that was in the last 5 to 10 years.

The United States is doing fine with its food supply the problem is most of the world outside of the Americas and Australia. We (Americas plus Aussie) feed the world. We have the most educated farmers in the world. Using the state of the science methods to grow the commodity crops of the western diet.

Then you go to the rest of the world. Europe has to import more food then anyone else in the world. Basically you have Spain as the only country that could feed it self with the other large countries of Europe handcuffing their farmers into inefficient methods for purely political reasons. There demand for food puts a large premium on the price felt by the poorer parts of the world. You have the continent of Africa where the staple crops are different then the west and don't have the money pouring into the research for best practices. They don't have the advanced chemical companies of the west to produce fertilizers nor do they have access or knowledge on how to best apply them.

Move to central Asia where the Mongols are back to pre Kahn methods. Move to southeast Asia and the major islands (minus Japan) where rice is the only thing you can grow economically and culturally. 2 million people mostly kids die because of the lack of vitamin A. And millions go blind. Golden Rice would be a life saver. Yeah yeah they can eat carrots and grow community gardens except for the whole its uneconomical and not enough land to make a dent.

Improving the nutrients of an indigenous plant to provide something that's missing, like golden rice, is a great thing, and I fully support it.

Hardly a great thing, it's called diversity. We would be growing a single crop with all nutrients in it with that reasoning. And the African kids who become blind because of the missing vitamin A are seriously suffering from malnutrition, they are not just missing vitamin A. Give them a superconcentrate broth to cook their white rice, or give them the means to grow vegetables and pulse, but that Golden Rice is just plain wrong, although it's more politically and ethically than medically.

Besides, anyone who buys that a corporation like Monsato is interested in making sure People around the World receive nutrient rich food, is not seeing the reality. I would believe it if the food was given away for free. It never is. Even US Aid is paid for by taxpayer funds.

Huh? This makes no sense. Monsanto produces very little in the way of crops. The farms the own and lease are mostly for testing and seed production. They don't actually grow food for market that is the farmers job where nearly all of them again are family owned. And even if the farmer gave it away you are asking a lot of people to work for nothing along the way before it even it hits port. First you have the grain operators that would have to forgo their fee, you have the train companies that would need to ship it. The processor and packagers that would need to do it for free another train trip for free all just to get to port. Its more economically just to buy it from market then try to coordinate all of the paper work required here.

Next up, you do know that Monsanto and the rest of the big ArgTech companies all the time allow humanitarian licenses on their IP? Syngenta has given millions in free research to the golden rice project. They work with small GMO projects all the time with little to no licensing costs. They give out blanket research licenses to nearly all accredited universities.

Quote:

Corporations cannot control food revenue without controlling food production. A corporation cannot control a plant that is made for free by Nature. Solution: control the seed production and ensure farmers have to buy from you every season.

Hippie nonsense that says nothing. Farmers don't have to buy seeds they don't want. In the case of corn farmers have not replanted seeds for nearly 80 years now. Soy and Cotton where moving this way before the introduction of GMOs and the tech agreements that go along with them.

But, lets get to what your comment really says which is farmers are dumb.

-- When "Roundup ready" crops became popular in the mid 1990s, farmers were enamored with-- the genetically-modified seeds built to withstand glyphosate, the active ingredient in Roundup,-- the most popular commercial weed killer. But after years of constant exposure, certain invasive-- plants have also developed a resistance, leading farmers to use more of the chemical. In some-- cases, the weeds have grown completely tolerant to the chemical, giving farmers fits.

-- The problem is most pronounced in the southeast where farmers have been growing "Roundup-- ready," cotton for years, according to Charles Benbrook, a Washington State University -- researcher who studies herbicide use. Farmers who grow genetically modified crops use-- about 25 percent more herbicides than farmers who use traditional seeds, he says. It's no-- different than the overuse of antibiotics that has led to resistance from bugs such as -- gonorrhea in the past year.

The Union of Concerned Scientists has a page on roundup ready crops as well.

-- Beginning around 2000, weeds growing in Roundup Ready crops began to develop resistance-- to Roundup (glyphosate), the Monsanto herbicide that Roundup Ready crops are genetically-- engineered to tolerate. By 2011, eight agriculturally important weeds in the U.S. had developed-- glyphosate resistance associated with Roundup Ready crops.

-- In response, farmers are increasing their overall herbicide use (see #2) and in some cases,-- returning to heavy tillage (plowing), which can increase soil erosion—thus reducing two of-- the sustainability benefits claimed for the Roundup Ready system.

That's cool and all, but I'll still choose not to consume them and demand their labeling. I'm all for science, but even so, it's not like money can't be used to ensure that experiments produce the desired results...and the companies making GMO foods have a LOT of money.

How about you pay for that instead? Do you realize how much of your non-GMO food is subsidized by GMO food? The profit made by Monsanto et al pales in comparison to the economic benefit they've provided for people who eat food everywhere (read: everyone) and people who like to breathe (read: everyone).

If GMO food didn't exist there would either be a couple billion more people starving to death, or a lot less rainforest in the world. There's no way around the math that the only reason we can support 7 billion people and still have forests is with the increased yields made possible by GMO food.

This is a very balanced article on the safety of gm foods and explains the state of affairs as it is today regarding the lack of communication between media and the scientists involved. However I would like to point out that the article fails to inform that there are very sophisticated techniques available and used today to remove all the " marker genes" that are used to generate the gm plant produced for food consumption and in fact EU regulations require that marker genes are absent in the final gm variety marketed. This was not mentioned in the article.

The GMO debate is one that is loaded with misinformation. The other concern is that Monsanto is a pretty slimy company. Their seeds don't produce plants that create more seeds, so farmers always have to buy high priced seeds from the company every season. That just seems unethical to me, but "it's just business" right?.

Monsanto's plants still produce seeds. The whole point is to produce more corn or beans which is the seed of the plant. This isn't like seedless grapes, where the good part is the fruit-- the whole point of buying Monsanto's seeds is to have higher yields (understand more seeds)

Monsanto has a contract with farmers that they can not use last year's crop to plant next year, yes to increase profits and as a business plan to protect their profits. Yes farmers have to buy high priced seeds. But farmers are free NOT to buy that brand, yes there are other seed corns out there.

Farmers today are highly educated and think about this for years-- they have done the calculations! While a small farmer (less than 40 acres as an example) couldn't make money buying Monsanto's seeds each year, larger operations more than make up the difference in yield and there fore profit.

And you mentioned Round Up: do a little math, is it better to spray 2 gallons of three different chemicals or 3 gallons of Round Up to kill weeds? Using Round Up results in less total chemicals being used in the field.

And note I don't work for Monsanto or in the Ag industry, just a farm kid who is amazed how little people know about modern farming.

Besides, anyone who buys that a corporation like Monsato is interested in making sure People around the World receive nutrient rich food, is not seeing the reality. I would believe it if the food was given away for free. It never is. Even US Aid is paid for by taxpayer funds.

Are you talking about Golden Rice? No that wasn't Monsanto it was Profs Ingo Potrykus (ETH Zurich) and Peter Beyer (Univ of Freiburg) Funded by the Gates Foundation.

Did someone working for one of the GMO producing companies write this article? GMOs are, to put it as nice as possible,: garbage. Some GMOs are no longer allowed as food for humans, however, companies producing said GMOswant this used as feed. If they can not get the OK for use as human food, changethe use to feed animals or as fertilizer and it's still in the human\ food chain. Because some pests are no longer effected by GMOs, farmers are now toldthey must also plant an area with non-GMO seeds. The idea, the pests willseek out and eat the non-GMO plants and not mess with the GMO plants.This reasoning is garbage. One thing that has happened...the GMO producers are blaming farmers forone reason some pests are no longer effected by GMOs designed to stopor kill them. They (the companies making GMOs) claim farmers are not planting enough non-GMO plants. The most telling thing about GMOs. Why would any company producing a food product "seeds" want a law enacted banning all lawsuits relatedto the product they make and sell. If it can cause harm to humans so what.That law tells the world: "eat our wonderful GMOs and if you do, the risk isall on you, the consumer. Last, most companies supplying food were proud of the ingredients used,now some companies want some items they use kept off the label. Why hide, from the consumer, what they will eat.